1. Field of the Invention
The present invention relates generally to fluid delivery devices. More particularly, the invention concerns an improved, ultra-low profile, multiple chamber fluid delivery apparatus for precise subdermal delivery over time of medicinal liquids to an ambulatory patient, the device including novel reservoir filling means.
2. Discussion of the Prior Art
A number of different types of liquid dispensers for dispensing medicaments to ambulatory patients have been suggested. Many of the devices seek either to improve or to replace the traditional hypodermic syringe that has been the standard for delivery of liquid medicaments such as insulin solution.
Those patients that require frequent injections of the same or different amounts of medicament, find the use of the hypodermic syringe both inconvenient and unpleasant. Further, for each injection, it is necessary to first draw the injection dose into the syringe, then check the dose and, after making certain that all air has been expelled from the syringe, finally, inject the dose. This cumbersome and tedious procedure creates an unacceptable probability of debilitating complications, particularly for the elderly and the infirm.
One example of the urgent need for an improved liquid delivery device for ambulatory patients can be found in the stringent therapeutic regimens used by insulin-dependent diabetics. The therapeutic objective for diabetics is to consistently maintain blood glucose levels within a normal range much as the normally functioning pancreas would do by secreting a very low level of extremely fast-acting insulin at a basal rate into the blood stream throughout the day and night.
As will be appreciated from the discussion that follows, the low profile apparatus of the present invention is uniquely suited to provide precise fluid delivery management at a low cost in those cases where a variety of precise dosage schemes are of utmost importance.
An additional important feature of the apparatus of the present invention is the provision of a novel reservoir filling means disposed on the underside of the base.
Because the embodiments of the invention described herein comprise improvements to the devices described in U.S. Pat. No. 5,957,891 issued to Kriesel et al on Sep. 28, 1999, this patent is hereby incorporated by reference in its entirety as though fully set forth herein.
With regard to the prior art, one of the most versatile and unique fluid delivery apparatus was developed by Kriesel and described in U.S. Pat. No. 5,205,820. The components of this novel fluid delivery apparatus generally include: a base assembly, an elastomeric membrane serving as a stored energy means, fluid flow channels for filling and delivery, flow control means, a cover and an ullage which comprises a part of the base assembly. Another unique multiple chamber, reservoir type fluid delivery apparatus developed by Kriesel is described in U.S. Pat. No. 5,336,188. This novel fluid delivery apparatus includes, an elastomeric membrane that serves as a stored energy means and cooperates with the base of the apparatus to define a multi-part reservoir.
Another useful liquid delivery device is that described in U.S. Pat. No. 5,514,097 issued to Knauer. The Knauer device comprises a medicament injection apparatus for subcutaneous or intramuscular delivery of a medicament that conceals the infusion needle behind a needle shroud. On apparatus activation, the needle is thrust forward, pushing the needle tip outside the needle shroud with enough force to puncture the skin. The needle is thus automatically introduced into the tissue at the proper needle/skin orientation. In the same action, the apparatus automatically dispenses an accurate pre-set dose.
U.S. Pat. No. 5,226,896 issued to Harris also described a useful prior art device. This device comprises a multidose syringe having the same general appearance as a pen or mechanical pencil. The Harris device is specifically adapted to provide for multiple measured injections of materials such as insulin or human growth hormones.
Still another type of liquid delivery device is disclosed in U.S. Pat. No. 4,592,745 issued to Rex et al. This device is, in principle, constructed as a hypodermic syringe, but differs in that it enables dispensing of a predetermined portion from the available medicine and in that it dispenses very accurate doses.
The present invention seeks to significantly improve over the prior art by providing a novel, ultra-low profile fluid delivery device having strategically configured, multiple fluid chambers and a unique filling means for filling the fluid chambers of the device.
It is an object of the present invention to provide an apparatus having a self-contained stored energy membrane for expelling fluids at a precisely controlled rate that is of a compact, laminate construction. More particularly, it is an object of the invention to provide such an apparatus which is of very low profile so that it can conveniently be used for the precise delivery of pharmaceutical fluids, such as endocrine type agents such as insulin, growth hormones and the like, into an ambulatory patient at controlled rates over extended periods of time.
It is another object of the invention to provide an apparatus of the aforementioned character that is highly reliable and very easy-to-use by lay persons in a non-hospital environment.
Another object of the invention is to provide an apparatus of the character described in the preceding paragraphs which includes novel reservoir filling means for conveniently filling the fluid reservoir of the device.
Another object of the invention is to provide an apparatus of the character described which includes a novel fill adapter which permits filling of the reservoir of the apparatus only with filling means of a specific construction, which is designed so that the fill adapter is irreversibly installed and, once installed, cannot be removed from the device housing.
Another object of the invention is to provide an apparatus such as that described in the preceding paragraph in which the reservoir fill means includes integrated structure to accept conventional prefilled pharmaceutical vials.
Another object of the invention is to provide an apparatus of the class described which further includes delivery means for precisely delivering medicinal fluids to the patient including the provision of a novel, dynamically mounted cannula assembly.
Another object of the invention is to provide an apparatus of the type described which includes indicator means for indicating fluid flow from the device reservoir.
Another object of the invention is to provide an apparatus of the character described which, due to its unique construction, can be manufactured inexpensively in large volume by automated machinery.
Other objects of the invention will become apparent from the discussion that follows.